Organic Chemistry II - Summary of Preparations

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Study GuideOrganic Chemistry IISummary of Preparations1.Preparations: Aryl Halides1.Halogenation of BenzeneWhat happens?Benzene undergoes halogenation in the presence of a halogen (X) and a Lewis acid catalyst(such as AlCl). This leads to the substitution of a hydrogen atom on the benzene ring with ahalogen atom.What’s used?A halogen (X) such as chlorine (Cl) or bromine (Br), and an AlClcatalyst.Reaction:

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Study Guide2.Sandmeyer ReactionWhat happens?In the Sandmeyer reaction, an amino group (-NH) on a benzene ring is converted to a halogen(usually bromine or chlorine) by first diazotizing the amine group with sodium nitrite (NaNO)and hydrochloric acid (HCl), followed by treatment with a copper halide (CuX).What’s used?Sodium nitrite (NaNO), hydrochloric acid (HCl), copper(I) halide (CuX), and the appropriatehalogen.Reaction:(with CuBr as the catalyst for bromine substitution)2.Preparations: Ethers1.Sulfuric Acid ProcessWhat happens?The sulfuric acid process involves the dehydration of alcohols to form ethers. Alcohol undergoesan acid-catalyzed elimination reaction with sulfuric acid (HSO), resulting in the formation ofan ether and water.

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Study GuideWhat’s used?Alcohol (R-OH) and concentrated sulfuric acid (HSO).Reaction:2.Williamson SynthesisWhat happens?The Williamson synthesis is an important method for forming ethers through an SN2 reaction. Itinvolves the reaction of an alkoxide ion (RO) with a primary alkyl halide (RX), leading to theformation of an ether.What’s used?An alkoxide ion (RO), an alkyl halide (RX), and heat (Δ).Reaction:3.Preparations: Alcohols1.Williamson Synthesis

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Study GuideWhat happens?The Williamson synthesis is used to prepare alcohols via the reaction of an alkoxide ion (RO)with a primary alkyl halide (RX) in a nucleophilic substitution reaction. This leads to theformation of an ether, which can be converted into an alcohol if water is added.What’s used?Alkoxide ion (RO), alkyl halide (RX), and water (HO).Reaction:2.Hydroboration-OxidationWhat happens?In the hydroboration-oxidation reaction, an alkene reacts with borane (BH) to form atrialkylborane intermediate, which is then oxidized using hydrogen peroxide (HO) to form analcohol.What’s used?Borane (BH), hydrogen peroxide (HO).Reaction:

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Study Guide3.Reduction of Aldehydes and KetonesWhat happens?Aldehydes and ketones can be reduced to alcohols using lithium aluminum hydride (LiAlH) as areducing agent.What’s used?Lithium aluminum hydride (LiAlH) and water (HO).Reaction:4.Reduction of Carboxylic Acids

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Study GuideWhat happens?Carboxylic acids can be reduced to alcohols using lithium aluminum hydride (LiAlH).What’s used?Lithium aluminum hydride (LiAlH) and water (HO).Reaction:5.Reduction of EstersWhat happens?Esters can be reduced to alcohols using lithium aluminum hydride (LiAlH), producing a primaryalcohol and an alcohol derived from the ester group.What’s used?Lithium aluminum hydride (LiAlH) and water (HO).Reaction:

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Study Guide6.Grignard Reagent with Aldehydes and KetonesWhat happens?Grignard reagents (RMgBr) react with aldehydes or ketones to form alcohols through nucleophilicaddition. The intermediate product is then treated with acid to form the alcohol.What’s used?Grignard reagent (RMgBr), acid (H).Reaction (Aldehyde):Key TakeawayWilliamson Synthesis:Alcohols can be synthesized by nucleophilic substitution between analkoxide and an alkyl halide.Hydroboration-Oxidation:Alkenes undergo hydroboration followed by oxidation to formalcohols.Reduction of Aldehydes, Ketones, Carboxylic Acids, and Esters:LiAlHreduces carbonylcompounds to alcohols.Grignard Reagent:Grignard reagents add to aldehydes and ketones, forming alcohols uponacid work-up.

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Study Guide4.Preparations: Aldehydes1.Oxidation of Primary AlcoholsWhat happens?Primary alcohols can be oxidized to aldehydes using an oxidizing agent like pyridiniumchlorochromate (PCC). The reaction occurs in the presence of a solvent like dichloromethane(CHCl).What’s used?Pyridinium chlorochromate (CHNHCrOCl) and dichloromethane (CHCl).Reaction:2.Reduction of Acyl HalidesWhat happens?Acyl halides (R-CO-Cl) are reduced to aldehydes using lithium tri-tert-butoxyaluminum hydride(LATB-H) at low temperatures.What’s used?Lithium tri-tert-butoxyaluminum hydride (LATB-H) and water (HO).

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Study GuideReaction:3.Reduction of EstersWhat happens?Esters can be reduced to aldehydes using diisobutylaluminum hydride (DIBAL-H) at lowtemperatures followed by hydrolysis.What’s used?Diisobutylaluminum hydride (DIBAL-H) and water (HO).Reaction:4.Reduction of NitrilesWhat happens?Nitriles (R-C≡N) can be reduced to aldehydes using diisobutylaluminum hydride (DIBAL-H)followed by hydrolysis.What’s used?Diisobutylaluminum hydride (DIBAL-H) and water (HO).
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